I got OEMs off of a now-defunct site (v6mustangstuff.com or something like that) for $250 shipped IIRC and got OEMs with carbon fiber insets f&r off of eBay for $350 shipped. I saw some in the 200 range a few months back, so just be patient. Do a search for 05-09 mustang leather & get notifications for it so you can check for possibilities every morning. Or if you want a really badass kit for some ching ($1300 IIRC), get MRT's Predator kit. Thats what I plan to do with my next ride when the OEM leather eventually wears. Id like to get it earlier than that for the door inserts though.
2010-2012 Mustang Predator Seats / Interior Kit - MRT
---------- Post added at 04:27 PM ---------- Previous post was at 04:20 PM ----------
P.S. Took a quick look at eBay and yeah, theres no good deals right now, which is why I suggest a saved search, so you can scoop some up when something good appears, because they usually go fast which is why youre probably not seeing any right now. Most of what is available are pricey Roush stuff, semi-rare colors, pieces and full seats (not covers).